JP2015010931A - Semiconductor pressure sensor device and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor pressure sensor device that can suppress corrosion even under a harsh environment such as in an exhaust system, and a manufacturing method of the semiconductor pressure sensor device.SOLUTION: A semiconductor pressure sensor device 100 comprises: a semiconductor substrate 1 having a recess 10 that serves as a vacuum standard chamber 9; a diaphragm 2a arranged on a surface of the semiconductor substrate 1; a distortion gage resistor 2; an aluminum wiring layer 4 arranged on the semiconductor substrate 1; an antireflection film which is a TiN film 5 arranged on the aluminum wiring layer 4; an adhesion-degree-securing and diffusion preventing film 7 which is a laminate film of a Cr film 7a and a Pt film 7b arranged on the TiN film 5; and an Au film 8 laminated on the adhesion-degree-securing and diffusion preventing film 7. Processing an end face 14 of a laminate metal film 13 including the Cr film 7a, the Pt film 7b and the Au film 8 into a tapered shape expanding toward the semiconductor substrate 1 prevents a dent from being formed on an end face of the adhesion-degree-securing and diffusion preventing film 7, suppressing corrosion by an exhaust gas.

Description

  The present invention relates to a semiconductor pressure sensor device used in various devices such as automobiles, medical devices, and industrial devices, for example, a semiconductor pressure sensor device used in a poor environment such as an automobile exhaust system, and a manufacturing method thereof. .

  FIG. 7 is an overall configuration diagram of the semiconductor pressure sensor device 500. A conventional semiconductor pressure sensor device 500 includes a semiconductor substrate 51 formed with a diaphragm 52a, a strain gauge resistor 52 and an integrated circuit (not shown) formed on the front surface side, and a recess 60 formed on the back surface of the semiconductor substrate 51. A glass substrate 61 fixed to the back surface of the semiconductor substrate 51 and a resin case 66 for storing the semiconductor substrate 51 and the glass substrate 61 are provided. A vacuum reference chamber 59 is formed by closing the recess 60 of the semiconductor substrate 51 with a glass substrate 61, thereby forming a semiconductor pressure sensor IC chip 501. The resin case 66 is provided with a metal terminal 69, and the semiconductor pressure sensor IC chip 501 is connected to the metal terminal 69 through a bonding wire 68 (Al wire or Au wire). The glass substrate 61 is fixed to the resin case 66 with an adhesive 67, and the surface of the semiconductor pressure sensor IC chip 501 is covered with a protective material such as a silicone gel 70.

  On the semiconductor substrate 51, an interlayer insulating film of a silicon oxide film 53, an aluminum wiring layer 54, a TiW film 57 which is an adhesion securing / diffusion preventing layer, and an Au film 58 are laminated. The function of the TiW film 57 serving as the adhesion securing / diffusion preventing layer improves the adhesion to the aluminum wiring layer 54 and prevents the Au atoms of the Au film 58 from diffusing into the aluminum wiring layer 54.

  Pressure is applied to the diaphragm 52a provided on the semiconductor pressure sensor IC chip 501 via a protective material such as a silicone gel 70. As described above, the strain gauge resistor 52 is provided on the diaphragm 52a, and the change in the resistance value of the strain gauge resistor 52 increases as the strain amount of the diaphragm 52a increases. The strain gauge resistor 52 constitutes a bridge circuit, converts the resistance change into a voltage change, and the voltage change is output to the outside via an analog circuit (integrated circuit) such as an amplifier circuit.

  Such a semiconductor pressure sensor device 500 is used as an intake pressure sensor for measuring the pressure of an intake system of an internal combustion engine (engine) such as an automobile. It is also used to detect system pressure. When used for pressure measurement in the intake system, the semiconductor pressure sensor device 500 is exposed only to relatively clean air or sprayed gasoline, so that the chemical resistance required for the semiconductor pressure sensor device 500 is mainly gasoline or the like. It was only resistant to fuel. Therefore, the electrodes and bonding wires of the integrated circuit are made of aluminum or an alloy mainly made of aluminum, and the resistance can be sufficiently secured by protecting the surface of the integrated circuit with the silicone gel 70 having high chemical resistance.

  However, since it is also exposed to corrosive substances generated from nitrogen compounds, sulfides, and the like discharged from the internal combustion engine when used for exhaust system pressure measurement, the semiconductor pressure sensor device 500 includes various corrosive substances. As a countermeasure against these problems, a technique of providing a Ti film and a Pd film for preventing corrosion on the surface of an aluminum electrode has been proposed (for example, Patent Document 1).

  Further, in the structure of Patent Document 1, it is assumed that the resistance to corrosion by nitrate ions caused by nitrogen oxides contained in the exhaust gas is insufficient, and a TiW film is used as an adhesion securing / diffusion preventing layer on the aluminum electrode, and the surface is made resistant to damage. A technique of covering with a highly corrosive Au film has been proposed (for example, Patent Document 2).

Further, Patent Document 3 describes a configuration (step structure) in which the diffusion prevention film projects laterally from the seal film in order to prevent undercutting of the diffusion prevention film.
The TiW film or Au film covering the surface of the aluminum wiring layer is formed by sputtering or vapor deposition, which is a general method for forming a metal film in a semiconductor, and etching for patterning the formed metal film is performed as follows: Wet etching or lift-off is used.

JP 10-153508 A Japanese Patent Application No. 2007-542184 Japanese Patent Application No. 2007-251158

  As described above, a plurality of films such as the adhesion securing / diffusion prevention layer made of the TiW film 57 and the highly corrosion-resistant Au film 58 are formed on the aluminum wiring layer 54 by sputtering or vapor deposition. When wet etching is used for the film formation, wet etching is performed using an etching solution suitable for each layer (Au film 58 and TiW film 57) in order from the upper layer. Therefore, side etching of the TiW film 57 which is an adhesion securing / diffusion prevention layer close to the aluminum wiring layer 54 becomes large. By this side etching, the end portion of the TiW film 57 between the Au film 58 having the highest corrosion resistance on the outermost surface and the passivation film 56 is retracted to form a minute gap 80 that is a depression (FIG. 8). FIG. 8 is a sectional view of the manufacturing process corresponding to the portion B in FIG.

When the gas reaches such a minute gap 80, the gas tends to become the liquid 81 due to the capillary condensation action.
On the other hand, the corrosion of the metal such as the TiW film 57 proceeds also by a nitrogen compound or sulfide in a gaseous state, but the progress of the corrosion is often accelerated by the presence of moisture. Therefore, nitrogen compounds, sulfides, water vapor, and the like that have entered the minute gap 80 in the gas state become the liquid 81 in the minute gap 80, which may lead to corrosion. This corrosion also occurs at the interface 82 between the TiW film 57 and the Au film 58 due to the addition of galvanic corrosion (corrosion between different metals) called a voltaic cell between two layers of metal (for example, the TiW film 57 and the Au film 58). To do. As this corrosion proceeds, the adhesion between the Au film 58 (pad electrode) and the TiW film 57 decreases, and peeling 83 occurs at the interface 82.

As described above, in a poor environment such as an exhaust system, the adhesion ensuring / diffusion preventing layer made of the TiW film 57 is difficult to use because of its low corrosion resistance.
Also, the lift-off method is not suitable for forming a fine pattern of several tens of μm because the pattern is formed by mechanically separating the metal film when removing the resist.

  Further, Patent Document 3 does not address corrosion when used as an exhaust system pressure sensor. Furthermore, there is no description about preventing the formation of the minute gap 80 and suppressing the corrosion by making the side walls of the TiW film 57 and the Au film 58 into a positive taper shape which will be described later.

  The present invention has been made in view of the above problems, and it is an object of the present invention to provide a semiconductor pressure sensor device capable of suppressing corrosion even in a poor environment such as an exhaust system and a method for manufacturing the same.

  In order to achieve the above object, according to the first aspect of the present invention, in the semiconductor pressure sensor device installed in the exhaust system of the internal combustion engine, the semiconductor pressure sensor device is disposed on the semiconductor substrate and is responsive to the pressure. And a strain gauge connected to the diaphragm and disposed on the diaphragm, a metal wiring layer connected to the strain gauge and disposed on the semiconductor substrate via an interlayer insulating film, and the metal wiring layer A passivation film having an opening through which the metal layer is exposed, an adhesion ensuring / diffusion preventing layer disposed on the exposed metal wiring layer and on the passivation film covering an end of the metal wiring layer, and ensuring the adhesion A conductive layer that constitutes a pad electrode laminated on the diffusion prevention layer, and the end face of the laminated metal layer constituted by the adhesion prevention and diffusion prevention layer and the conductive layer is on the semiconductor substrate side Towards a positive tapered or stepped shapes and configurations spread.

According to the second aspect of the present invention, in the first aspect of the present invention, the glass substrate may be fixed to the back surface of the semiconductor substrate by electrostatic bonding.
According to a third aspect of the present invention, in the first or second aspect, the metal wiring layer is an aluminum wiring layer, and the adhesion securing / diffusion prevention layer is the semiconductor. A Cr film and a Pt film or a Ti film and a Pt film may be laminated upward from the substrate side, and the conductive layer may be an Au film laminated on the Pt film.

  According to the invention described in claim 4 of the claims, in the invention described in claim 1 or 2, the adhesion ensuring / diffusion preventing layer is a single layer film of either a Cr film or a Ti film. In addition, the conductive layer may be a Pt film or an Au film.

  According to the invention described in claim 5 of the claims, in the invention described in any one of claims 1 to 4, between the metal wiring layer and the adhesion securing / diffusion preventing layer. An antireflection film may be interposed.

According to the invention described in claim 6, it is preferable that the antireflection film is a TiN film in the invention described in claim 5.
According to the invention described in claim 7, the method for manufacturing a semiconductor pressure sensor device according to claim 5 or 6 includes the step of forming the antireflection film on the metal wiring layer. A step of forming the passivation film having an opening, a step of fixing the glass substrate to the back surface of the semiconductor substrate by electrostatic bonding, an adhesion ensuring / diffusion preventing layer, and the conductive layer as the antireflection film. And a laminated metal layer forming step formed on the passivation film, wherein the laminated metal layer forming step forms the adhesion securing / diffusion preventing layer and the conductive layer on the entire surface side of the semiconductor substrate by sputtering. A step of forming a film, a step of selectively forming a resist mask on the formed conductive layer, and securing and preventing diffusion of the conductive layer by ion milling. The the method of manufacturing a semiconductor pressure sensor device and a step of etching.

  Moreover, according to invention of Claim 8 of Claim, in the manufacturing method of the semiconductor pressure sensor apparatus as described in any one of the said Claims 1-6, of the end surface of the said laminated metal layer The positive taper shape may be formed by ion milling in which Ar ions collide with the laminated metal layer through a mask to perform etching.

  According to the invention described in claim 9, the surface of the laminated metal layer according to the invention described in claim 8 is based on a direction perpendicular to the range axis of the Ar ions. It is good to incline downward so that it becomes an acute angle.

  According to the invention described in claim 10 of the claims, in the invention described in claim 9, the range axis of the Ar ions is horizontal, and the direction perpendicular to the range axis is used as a reference. The angle θ at which the surface of the laminated metal layer is inclined downward is preferably 0 ° ≦ θ ≦ 50 °.

According to the invention described in claim 11 of the claims, in the invention described in claim 10, the angle θ is preferably 10 ° ≦ θ ≦ 50 °.
According to the invention described in claim 12 of the claims, in the invention described in claim 8, the glass substrate is preferably fixed to the back surface of the semiconductor substrate by electrostatic bonding.

  According to the present invention, it is possible to manufacture a semiconductor pressure sensor device that can suppress corrosion even in a poor environment such as an exhaust system and a manufacturing method thereof.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram of the semiconductor pressure sensor apparatus 100 of 1st Example based on this invention, (a) is a whole block diagram, (b) is principal part sectional drawing of the semiconductor pressure sensor IC chip 101. It is principal part sectional drawing of the semiconductor pressure sensor apparatus 100a which shows the modification of the semiconductor pressure sensor apparatus 100 shown in FIG. It is principal part sectional drawing of the semiconductor pressure sensor apparatus 200 of 2nd Example which concerns on this invention. It is principal part manufacturing process sectional drawing of the semiconductor pressure sensor apparatus 100 of 3rd Example concerning this invention. FIG. 5 is a cross-sectional view of the essential part manufacturing process of the semiconductor pressure sensor device 100 of the third embodiment according to the present invention continued from FIG. 4. FIG. 6 is a diagram illustrating an ion milling process. 1 is an overall configuration diagram of a semiconductor pressure sensor device 500. FIG. FIG. 8 is a manufacturing process cross-sectional view corresponding to part B of FIG. 7.

Embodiments will be described in the following examples.
Example 1
1A and 1B are configuration diagrams of a semiconductor pressure sensor device 100 according to a first embodiment of the present invention. FIG. 1A is an overall configuration diagram, and FIG. 1B is a main part of a semiconductor pressure sensor IC chip 101. It is sectional drawing.

  In FIG. 2A, a semiconductor pressure sensor device 100 is formed on a semiconductor substrate 1 on which a diaphragm 2a, a strain gauge resistor 2 and an integrated circuit (not shown) formed on the front surface side are formed, and a back surface of the semiconductor substrate 1. A recess 10, a glass substrate 11 fixed to the back surface of the semiconductor substrate 1, and a resin case 16 for storing the semiconductor substrate 1 and the glass substrate 11. The vacuum reference chamber 9 is formed by closing the concave portion 10 of the semiconductor substrate 1 with the glass substrate 11, and the semiconductor pressure sensor IC chip 101 is formed. The resin case 16 is provided with a metal terminal 19, and the semiconductor pressure sensor IC chip 101 is connected to the metal terminal 19 via a bonding wire 18 (Al wire or Au wire). The glass substrate 11 is fixed to the resin case 16 with an adhesive 17, and the surface of the semiconductor pressure sensor IC chip 101 is covered with a protective material such as a silicone gel 20.

  In FIG. 2B, a semiconductor pressure sensor IC chip 101 constituting the semiconductor pressure sensor device 100 is disposed on the surface of the semiconductor substrate 1 having the recess 10 serving as the vacuum reference chamber 9 and on the surface of the semiconductor substrate 1. A diaphragm 2a and a strain gauge resistor 2 electrically connected to the diaphragm 2a are provided. An interlayer insulating film which is a silicon oxide film 3 disposed on the semiconductor substrate 1 and electrically connected to the strain gauge resistor 2 and an aluminum which is an Al—Si—Cu film disposed on the silicon oxide film 3 And a wiring layer 4. An antireflection film that is a TiN film 5 disposed on the aluminum wiring layer 4 and a passivation film 6 that is disposed on the TiN film 5 and includes an opening and a silicon oxide film 6a and a silicon nitride film 6b. . The adhesion securing / diffusion preventing film 7 which is a laminated film (see FIG. 4) of the Cr film 7a and the Pt film 7b disposed on the TiN film 5 exposed from the opening, and the adhesion securing / diffusion preventing film. 7 is provided with an Au film 8 (which becomes an Au electrode) laminated on the substrate 7. Moreover, the glass substrate 11 electrostatically joined to the semiconductor substrate 1 (back surface) on the opening side of the recess 10 is provided. The vacuum reference chamber 9 is formed by fixing the glass substrate 11 to the semiconductor substrate 1.

  The original function of the TiN film 5 serving as the antireflection film is to prevent halation that occurs during photolithography exposure. In addition to this function in the present invention, there is a function to suppress a large hillock generated in the aluminum wiring layer 4 at a temperature (about 400 ° C.) when the glass substrate 11 is electrostatically bonded to the semiconductor substrate 1. Therefore, the film thickness of the Au film 8 can be reduced.

Further, the laminated film of the Cr film 7a and the Pt film 7b used as the adhesion ensuring / diffusion preventing layer 7 has a function of preventing corrosion even in a poor environment such as an exhaust system.
The Cr film 7a, the Pt film 7b, and the Au film 8 are the laminated metal layer 13 laminated upward from the semiconductor substrate 1 side, and the end surface 14 of the laminated metal layer 13 faces the semiconductor substrate 1 side. To a taper shape (referred to herein as a positive taper shape 15). By processing this positive taper shape 15, a recess is formed on the end face of the adhesion securing / diffusion prevention film 7 composed of the Cr film 7a and the Pt film 7b. Since no depression is formed, the corrosive gas in the gaseous state that has reached the Au film 8 (pad electrode) is unlikely to be in a liquid state, and corrosion due to exhaust gas at this location can be suppressed. As a result, the interface between the Cr film 7a, which is the adhesion securing / diffusion prevention film 7, and the Pt film 7b is prevented from peeling off due to corrosion. The Cr film 7a of the adhesion securing / diffusion prevention film 7 is in close contact with the underlying TiN film 5 (the aluminum wiring layer 4 in the absence of the TiN film 5), the underlying aluminum wiring layer 4 and the upper Au film. It functions to prevent diffusion between the membranes 8. The Pt film 7b functions to prevent diffusion between the underlying aluminum wiring layer 4 and the upper Au film 8.

  In the above, the laminated metal layer 13 is composed of three layers of the Cr film 7a, the Pt film 7b, and the Au film 8, but the Cr film 7a and the Au film 8, the Pt film 7b and the Au film 8 are directed upward from the semiconductor substrate 1 side. The film 8 may be composed of two layers such as a Cr film 7a and a Pt film 7b and a Ti film and a Pt film 7b. That is, as the laminated metal layer 13, in addition to the three-layer structure of the Cr film 7a, the Pt film 7b, and the Au film 8, the three-layer structure of the Ti film, the Pt film, and the Au film, the Cr film, the Au film, and the Ti film There are two-layer structures such as an Au film, a Cr film and a Pt film, and a Ti film and a Pt film. By making the end surface 14 of these laminated metal layers 13 into the regular taper shape 15, corrosion is prevented and peeling is prevented. In this corrosion, galvanic corrosion due to the battery effect generated between the metal films is also involved.

The aluminum wiring layer 4 includes an Al—Si film (an Al film containing about 1% Si) or an Al—Si—Cu film (an Al film containing about 1% Si and about 0.5% Cu). ).
The adhesion securing / diffusion preventing layer 7 may be a single layer film of either a Cr film or a Ti film. Further, instead of the Au film 8, a Pt film may be used. Moreover, you may comprise the laminated metal layer 13 by the said combination.
<Modification 1>
FIG. 2 is a cross-sectional view of a main part of a semiconductor pressure sensor device 100a showing a modification of the semiconductor pressure sensor device 100 shown in FIG. This figure is a cross-sectional view of the main part of the semiconductor pressure sensor IC chip 101a.

The difference from FIG. 1 is that the antireflection film composed of the TiN film 5 inserted between the aluminum wiring layer 4 and the adhesion securing / diffusion prevention layer 7 is deleted. Also in this case, by forming the side surface of the laminated metal layer 13 to have the positive taper shape 15, the formation of the depression is suppressed, so that the same effect as in FIG. 1 can be obtained. However, since there is no TiN film 5 which is an antireflection film, the generation of large hillocks from the aluminum wiring layer 4 cannot be suppressed.
(Example 2)
FIG. 3 is a cross-sectional view of an essential part of a semiconductor pressure sensor device 200 according to the second embodiment of the present invention. This figure is a cross-sectional view of the main part of the semiconductor pressure sensor IC chip 201.

The difference from FIG. 1 is that the end faces 14 of the Cr film 7a, the Pt film 7b, and the Au film 8 constituting the laminated metal layer 13 have a stepped shape 21 that widens toward the semiconductor substrate side. Also in this case, the formation of the depression is suppressed.
Example 3
4 and 5 show a method for manufacturing the semiconductor pressure sensor device 100 according to the third embodiment of the present invention, and are cross-sectional views of the main part manufacturing process shown in the order of the processes.
(1) In FIG. 4A, a strain gauge resistor 2 is formed on the surface side of the semiconductor substrate 1, and a silicon oxide film 3 as an interlayer insulating film is formed thereon. Subsequently, an aluminum wiring layer 4 is formed on the silicon oxide film 3. Subsequently, a TiN film 5 as an antireflection film is formed on the aluminum wiring layer 4. A passivation film 6 composed of a silicon oxide film 6a and a silicon nitride film 6b is formed so as to cover the periphery of the ends of the TiN film 5 and the aluminum wiring layer 4.
(2) In FIG. 4B, an adhesion securing / diffusion preventing layer 7 composed of a Cr film 7a and a Pt film 7b is formed on the TiN film 5 by sputtering.
(3) In FIG. 4C, an Au film 8 is formed on the adhesion securing / diffusion prevention layer 7 by sputtering. After the semiconductor substrate 1 is ground from the back surface to reduce the thickness, the recess 10 is formed. Subsequently, the glass substrate 11 is attached to the back surface. By this sticking, the concave portion 10 is closed by the glass substrate 11 to form the vacuum reference chamber 9. In addition, this bonding is performed by electrostatic bonding (anodic bonding) at a high temperature of about 400 ° C., but since the aluminum wiring layer 4 is covered with the TiN film 5 which is an antireflection film, the aluminum wiring layer 4 The occurrence of large hillocks is suppressed. Therefore, the thickness of the adhesion ensuring / diffusion preventing layer 7 and the Au film 8 can be reduced.
(4) In FIG. 5D, a resist mask 12 is coated on the Au film 8 immediately above the aluminum wiring layer 4. FIG. 5D is an enlarged view of a portion A in FIG.
(5) In FIG. 5E, the laminated metal layer 13 of the Cr film 7a, the Pt film 7b, and the Au film 8 is dry-etched by ion milling, and the end face 14 of the laminated metal layer 13 is processed into a positive taper shape 15. Since this ion milling has a higher etching rate than ordinary dry etching, the processing time can be shortened. By forming the positive taper shape 15 on the end face 14 of the laminated metal layer 13, formation of a depression (corresponding to the minute gap 80 in FIG. 8) is prevented. Further, the portion of the laminated metal layer 13 having the positive taper shape 15 by this ion milling becomes a pad electrode.

  Thereafter, the semiconductor pressure sensor IC chip 101 is obtained by dicing the semiconductor substrate 1 and the bonded glass substrate base 11 together. The semiconductor pressure sensor IC chip 101 is fixed and stored in the resin case 16 with an adhesive 17, and the Au film 8 constituting the pad electrode and the metal terminal 19 of the resin case 16 are connected by a bonding wire 18 made of gold. Subsequently, the silicone gel 20 is filled to form the semiconductor pressure sensor device 100 shown in FIG.

  FIG. 6 is a diagram for explaining the ion milling process of FIG. The semiconductor substrate 1 with the glass substrate 11 is tilted, and Ar ions 22 traveling straight are made to collide with the surface of the laminated metal layer 13 (irradiate Ar ion beam) to perform ion milling. Is processed into a positive taper shape 15. The surface of the semiconductor substrate 1 (the back surface of the glass substrate 11) is inclined at an angle θ with respect to the vertical direction 24 with respect to the range axis 23 (Ar ion beam axis) of the Ar ions 22 running in the horizontal direction. In this way, by tilting the surface of the semiconductor substrate 1 and rotating the semiconductor substrate 1, the scattered matter 25 protruding from the laminated metal layer 13 by ion milling falls in the gravity direction 26 and adheres to the surface of the semiconductor substrate 1 again. Is prevented. By preventing the adhesion, residues of the laminated metal layer 13 can be prevented. In addition, the Ar ion source can be prevented from being contaminated with the scattered matter 25. The tilting angle θ may be 0 ° ≦ θ ≦ 50 °.

  When this angle θ is less than 0 ° (the surface of the semiconductor substrate faces upward at a minus angle), redeposition tends to occur. On the other hand, when the angle exceeds 50 °, shadows (shadows) are formed due to the thickness of the mask, and the collision density of Ar ions at the etching site is reduced, and the etching rate of ion milling is reduced. Therefore, preferably 10 ° ≦ θ ≦ 50 °.

  Even when the semiconductor substrate 1 is placed horizontally and Ar ions collide with the surface of the laminated metal layer 13 from the vertical direction, the positive tapered shape 15 can be formed on the end face 14 of the laminated metal layer 13. However, when the surface of the semiconductor substrate 1 is facing upward, the scattered matter 25 tends to adhere to the surface of the semiconductor substrate 1, so a measure to prevent the attachment is necessary. On the other hand, when the surface of the semiconductor substrate 1 is directed downward, it is necessary to take measures to prevent the scattered matter 25 from dropping and adhering to the Ar ion source disposed immediately below the semiconductor substrate 1. Therefore, these measures may be unnecessary by setting the angle (0 ° ≦ θ ≦ 50 °).

  In addition to the semiconductor pressure sensor devices 100, 200, and 300 used in a poor environment such as an exhaust system, a semiconductor physical quantity sensor device such as a semiconductor acceleration sensor device is used in a poor environment such as an exhaust system. In this case, the configuration of the present invention is effective.

  The present invention can also be applied to a sensor for measuring a differential pressure between the front surface side and the back surface side of the diaphragm 2a by providing a through hole communicating with the diaphragm 2a in the glass substrate 11. Further, the present invention can be applied to a semiconductor pressure sensor device in which a vacuum reference chamber is formed by providing a cavity in the semiconductor substrate 1 without using the glass substrate 11.

DESCRIPTION OF SYMBOLS 1 Semiconductor substrate 2 Strain gauge resistance 2a Diaphragm 3 Silicon oxide film 4 Aluminum wiring layer 5 TiN film 6 Passivation film 6a Silicon oxide film 6b Silicon nitride film 7 Adhesion ensuring / diffusion prevention layer 7a Cr film 7b Pt film 8 Au film 9 Vacuum Reference chamber 10 Recess 11 Glass substrate 12 Resist mask 13 Laminated metal layer 14 End face 15 Positive taper shape 16 Resin case 17 Adhesive 18 Bonding wire 19 Metal terminal 20 Silicone gel 21 Staircase shape 22 Ar ion 23 Range axis 24 Vertical direction 25 Scattering Object 100, 100a, 200 Semiconductor pressure sensor device 101, 101a, 201 Semiconductor pressure sensor IC chip

Claims (12)

In a semiconductor pressure sensor device installed in an exhaust system of an internal combustion engine, a diaphragm disposed on a semiconductor substrate and distorted according to pressure, a strain gauge connected to the diaphragm and disposed on the diaphragm, and connected to the strain gauge A metal wiring layer disposed on the semiconductor substrate via an interlayer insulating film, a passivation film having an opening through which the metal wiring layer is exposed, and the exposed metal wiring layer and an end of the metal wiring layer. An adhesion ensuring / diffusion preventing layer disposed on the passivation film covering a portion, and a conductive layer constituting a pad electrode laminated on the adhesion securing / diffusion preventing layer. A semiconductor having a positive taper shape or a staircase shape in which an end face of a laminated metal layer composed of a diffusion prevention layer and the conductive layer extends toward the semiconductor substrate side A force sensor device. The semiconductor pressure sensor device according to claim 1, wherein a glass substrate is fixed to the back surface of the semiconductor substrate by electrostatic bonding. The metal wiring layer is an aluminum wiring layer, and the adhesion securing / diffusion prevention layer is a laminated film of a Cr film and a Pt film or a laminated film of a Ti film and a Pt film from the semiconductor substrate side upward, The semiconductor pressure sensor device according to claim 1, wherein the conductive layer is an Au film laminated on the Pt film. 3. The semiconductor pressure sensor device according to claim 1, wherein the adhesion securing / diffusion preventing layer is a single layer film of either a Cr film or a Ti film, and the conductive layer is a Pt film. The semiconductor pressure sensor device according to any one of claims 1 to 4, wherein an antireflection film is interposed between the metal wiring layer and the adhesion ensuring / diffusion prevention layer. The semiconductor pressure sensor device according to claim 5, wherein the antireflection film is a TiN film. In the manufacturing method of the semiconductor pressure sensor device according to claim 5 or 6,
Forming the antireflection film on the metal wiring layer;
Forming the passivation film having an opening;
Fixing the glass substrate to the back surface of the semiconductor substrate by electrostatic bonding;
The laminated metal layer forming step of forming the adhesion ensuring / diffusion preventing layer and the conductive layer on the antireflection film and the passivation film,
The laminated metal layer forming step includes a step of forming the adhesion securing / diffusion prevention layer and the conductive layer on the entire surface side of the semiconductor substrate by sputtering, and a resist mask selectively on the formed conductive layer. And a step of etching the conductive layer and the adhesion securing / diffusion prevention layer by ion milling. A method of manufacturing a semiconductor pressure sensor device, comprising: 7. The method of manufacturing a semiconductor pressure sensor device according to claim 1, wherein a positive taper shape of an end face of the laminated metal layer collides Ar ions with the laminated metal layer through a mask. A method of manufacturing a semiconductor pressure sensor device, characterized by being formed by ion milling for etching. 9. The method of manufacturing a semiconductor pressure sensor device according to claim 8, wherein the surface of the laminated metal layer is tilted downward so as to have an acute angle with respect to a direction perpendicular to the range axis of the Ar ions. The angle θ at which the surface of the laminated metal layer is inclined downward with respect to the vertical direction with respect to the range of the Ar ion is set to 0 ° ≦ θ ≦ 50 °. A method for manufacturing a semiconductor pressure sensor device according to claim 9. The method of manufacturing a semiconductor pressure sensor device according to claim 9, wherein the angle θ is 10 ° ≦ θ ≦ 50 °. The method for manufacturing a semiconductor pressure sensor device according to claim 8, wherein the glass substrate is fixed to the back surface of the semiconductor substrate by electrostatic bonding.

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